Ghee has been the MVP in my kitchen. It’s a type of clarified butter, where the water is boiled off and the milk solids are toasted before being strained out. This gives ghee a slightly nutty flavor and greatly raises the smoke point, making it suitable for high heat cooking. It’s easy - if a little tedious - to make at home, and it’s great for cooking (and seasoning, IMO) with cast iron.
Plain butter has a low smoke point because the milk solids burn easily. Clarifying the butter removes those solids, leaving behind just the butter fat (and some water), which has a smoke point around 480°F. It also gives the butter a much longer shelf life, as those solids are what go rancid more quickly. To clarify butter, you just heat it up until the solids settle to the bottom, then skim off the foam and pour the fat off the top (a fine mesh sieve makes this easier).
Alternatively, you can continue to heat the butter for long enough to boil all the water off. Doing so will brown the milk solids sitting at the bottom, which imparts a nutty flavor to the butter, even though you will filter out the browned solids. This is ghee and is what I make and use.
It is my go-to cooking fat anytime I use my cast iron or carbon steel. It’s nice to be able to get a bit of buttery flavor when searing at high heat.